"That's so, and it's also pretty futile getting angry at somebody who's been dead two hundred years, but why couldn't they say Wednesday, or Monday, or Saturday, or whatever?" He checked back in the astronomical handbook, and the photostated pages of the old almanac, and looked over his calculations. "All right, here's the angle of the shadow, and the compass-bearing. I had a look, yesterday, when I was taking the local citizenry on that junket. The old baseball diamond at Forbes Field is plainly visible, and I located the ruins of the Cathedral of Learning from that. Here's the above-sea-level altitude of the top of the tower. After you've landed us, go up to this altitude--use the barometric altimeter, not the radar--and hold position." Loudons leaned forward from the desk to the contraption Altamont had rigged in the nose of the helicopter--one of the telescope-sighted hunting rifles clamped in a vise, with a compass and a spirit-level under it. "Rifle's pointing downward at the correct angle now?" he asked. "Good. Then all I have to do is hold the helicopter steady, keep it at the right altitude, level, and pointed in the right direction, and watch through the sight while you move the flag around, and direct you by radio. Why wasn't I born quintuplets?" "Mr. Altamont! Dr. Loudons!" a voice outside the helicopter called. "Are you ready for us, now?" Altamont went to the open door and looked out. The old Toon Leader, the Reader, Toon Sarge Hughes, his son, and four young men in buckskins with slung rifles, were standing outside. "I have decided," the Tenant said, "that Mr. Rawson and Sarge Hughes and I would be of more help than an equal number of younger men. We may not be as active, but we know the old ruins better, especially the paths and hiding places of the Scowrers. These four young men you probably met last evening; it will do no harm to introduce them again. Birdy Edwards; Sholto Jiminez; Jefferson Burns; Murdo Olsen." "Very pleased, Tenant, gentlemen. I met all you young men last evening; I remember you," Altamont said. "Now, if you'll all crowd in here, I'll explain what we're going to try to do." He showed them the old picture. "You see where the shadow of a tall building falls?" he asked. "We know the location and height of this building. Dr. Loudons will hold this helicopter at exactly the position of the top of the building, and aim through the sights of the rifle, there. One of you will have this flag in his hand, and will move it back and forth; Dr. Loudons will tell us when the flag is in the sight of the rifle." "He'll need a good pair of lungs to do that," Verner Hughes commented. "We'll use radio. A portable set on the ground, and the helicopter's radio set." He was met, to his surprise, with looks of incomprehension. He had not supposed that these people would have lost all memory of radio communication.